Apparatus for molding thermoplastic material



Oct. 2, 1951 E. C. QUEAR El AL. APPARATUS FOR HOLDING THERMOPLASTIC MATERIAL Filed Dec. 13, 1947 19 Sheets-Sheet l 2, 1951 E. c. QUEAR ET AL.

APPARATUS FOR MOLDING THERMOPLASTIC MATERIAL Filed Dec. 13, 1947 19 Sheets-Sheet 2 O a, w! m m 1 m1,

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E. C. QUEAR El AL APPARATUS FOR MOLDING Tl-IERHOPLAS'IIC MATERIAL Oct. 2, 1951 19 Sheet-Sheet 8 Filed Dec. 13, 1947 INVHVTORS ll}.-..:.iiwhhhwHflwnvHF w a Oct. 2, 1951 E. c. QUEAR ET AL APPARATUS FOR MOLDING THERMOPLASTIC MATERIAL Fild Dec. 13, 1947 19 Sheets-Sheet 9 NSW am JNYENTORS E. c. QUEAR El AL 2,569,535

' APPARATUS FOR MOLDING THERMOPLASTIC MATERIAL 19 Sheets-Sheet 10 Oct. 2, 1951 Filed Dec. 13, 1947 2, 1951 g, QUEAR ET AL 2,569,535

APPARATUS FOR 140mm: THERMOPLASTIC MATERIAL Filed Dec. 13. 1947 v 19 Sheets-Sheet 11 INVENTORS Oct. 2, 1951 E. c. QUEAR ET AL APPARATUS FOR MOLDING THERMOPLASTIC MATERIAL 19 Sheets-Sheet 12 Filed Dec.

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APPARATUS FOR MOLDING Tl-IERHOPLKSIIC MATERIAL Filed Dec. 13, 1947 19 Sheets-Sheet 15 N te: fiddsaknqid M5 is MSL or M53 m 72 56 5d 613 solenoid 5 a5 55 or 552 in 7'2'9'56 IN VEN TOR) 1951 E. c. QUEAR H m. 2,569,535

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APPARATUS FOR MOLDING THERMOPLASTIC MATERIAL Filed Dec. 13, 1947 19 Sheets-Sheet 15 00L 2, 1951 c, QUEAR ET A 2,569,535

APPARATUS FOR MOLDING THERMOPLASTIC MATERIAL Filed Dec. 13, 1947 H 19-Sheets-Sheet 16 I N VEN TOR.

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APPARATUS MOLDING THERMOPLASTIC MATERIAL l9 Sheets-Sheet 17 Filed Dec. 13, 1947 Oct. 2, 1951 E. c. QUEAR El AL APPARATUS F'OR MOLDING THERMOPLASTIC MATERIAL 19 Sheets-Sheet 18 Filed Dec. 13, 1947 wt mt w w wxkw. k \M b QM \QN NN 19 Sheets-Shet 19 7W5 'W MIME/ZED Q-QWQ NU E. c. QUEAR Er AL APPARATUS FOR MOLDING THERMOPLASTIC MATERIAL Uct. 2, 1951 Filed Dec. 13, 1947 QR EMWRNE wwtt wwsu N Patented Oct. 2, 1951 UNITED STATES PATENT OFFICE-I APPARATUS FOR MOLDING THERMO- PLASTICMATERIAL Application December 13, 1947, Serial'No. 791,520

-6 Claims. 1

This invention relates to the art of molding thermosetting plastic compounds. The copending applications of C. A. Nichols, et al., Serial No. 692,274, filed August 22, 1946 now Patent No. 2,523,137 and Serial No. 774,592, filed September 17, 1947 now Patent No. 2,531,524 disclose apparatuses for preheating comminuted molding material and dropping it into the open injection cylinder of a heated lower mold whose mold cavities are connected by runners with the cylinder. Immediately after charging it, the lower mold is moved under a. heated upper mold which is caused to descend upon it with pressure and a ram or piston in the injection cylinder is caused to ascend to force the preheated material into the cavities provided by the engaging molds; and the material is cured under pressure and heat derived from the molds. The equipment disclosed in these applications has proved to he satisfactory in molding relatively small parts, for example, the molded parts of electric switches used on automobiles.

An object of the invention is to improve the apparatus stated above in order to facilitate the molding of relatively larg articles such as ignition distributor caps and ignition coil case covers. It has been discovered that the molding of relatively large articles as well as smaller ones can be facilitated if the preheated, loose, comminuted mold material is briquetted while hot before being placed while hot in the mold injection cylinder. The reasons for this are not entirely known but it is believed that compressing the preheated material tends to equalize the temperature of the mass of material and tends to expel from the mass vapors of volatile matter which each preheated particle gives off. Whatever the reasons may be, when the hot briquette of preheated material is compressed in the injection cylinder of the lower mold, it readily fills the mold cavities completely.

A further object is to provide apparatus by which the briquetting step can be rapidly effected. To this end, the invention provides a combined preheatingand briquetting unit by which a predetermined mass of molding material is preheated and discharged into the open end of a briquetting cylinder. The cylinder is then closed by a plate and a ram in the cylinder forces the material against the plate to form a briquette or pill which the ram ejects from the cylinder after the plate is retracted.

A further object of the invention is to provide 2 briquetting unit located between them and control apparatus which causes the presses to operate in overlapping cycles, one-half cycle out of phase for example, and which causes said unit to provide briquettes alternately for the two presses according to their needs.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a plan view of the preheating and briquetting unit embodying the present invention.

Fig. 2 is a view taken in the direction of arrow 2 of Fig. 1 showing the large supply hopper mounted upon the frame work of the preheating and briquetting unit.

Figs. 3 and 4 together constitute a side elevation of the heating and briquetting unit.

Figs. 5 and 6 are sectional views respectively on lines 5-5 and 6-45 of Fig. 4.

Fig. 7 is a sectional view on line 11 of Fig. 4 and is drawn to a larger scale.

Figs. 8, 9, 10 and 11 are sectional views taken respectively on the lines 88, 9-9, Ill-l0 and "-4 l of Fig.7.

Fig. 12 is a chart showing the operation of the cams shown in Figs. 9, 10 and 11.

Figs. 13 and 14 together form a. front view of the preheating apparatus.

Fig. 15 is a left side view of the apparatus shown in Figs. 13 and 14.

Fig. 16 is a fragmentary sectional view on the line I6l6 of Fig. 15.

Figs. 17 and 18 together form a sectional view on the line ll--l'l of Fig. 3.

Fig. 19 is a fragmentary view in the direction of arrow 19 of Fig. 17.

Fig. 20 is a fragmentary sectional view on the line 20-20 of Fig. 21.

Fig. 21 is a sectional view on the line 2l-2l of Fig. 1.

Fig. 22 is a side view looking in the direction of arrow 22 of Fig. 1.

Fig. 23 is a side view of a hopper looking in the direction of arrow 23 of Fig. 13.

Fig. 24 is a fragmentary sectional view on the line 24-24 of Fig. 22.

Fig. 25 is a fragmentary sectional view on the line 25-25 of Fig. 22.

Fig. 26 is a front view of the roller cleaner assembly. Fig. 27 is a sectional view on the line 2|-2| of Fig. 26. 

